Long range projectiles have historically included either liquid-fuel motors or sold-fuel motors. There are drawbacks and benefits associated with each type of motor.
Liquid-fuel motors provide good energy management because they can be turned on and off during operation of the projectile. However, liquid fuels are quite toxic such that they are difficult to store safely, especially in enclosed and crowded environments. In addition, liquid fuels often degrade during long term storage.
Solid-fuel motors are typically easier to store but usually provide only one or two thrust operations (i.e., burns). A typical solid-fuel motor provides axial thrust but might also incorporate lateral thrusters which increase the overall weight of the projectile. In addition, the need for axial and lateral thrusters usually (i) requires valuable space within the projectile making it difficult to efficiently design the projectile; and/or (ii) makes it difficult to efficiently propel the projectile due to hardware complexity associated with having axial and lateral thrusting capability.
There has been some recent development of new propulsion technologies. However, these new propulsion technologies require further development and analysis of operation, transportation, logistics, and long-term storage capabilities.
There is a need for a projectile that includes a solid-fuel propulsion system yet allows the speed of the projectile to be adjusted in a variety of ways in order to acquire a target. The projectile should also be able to cost effectively incorporate existing solid-fuel motors into the propulsion system for safe operation and storage.